Freight, Pzb, And Speed Limits

Just trying to piece together some information about driving freight services on the German routes, based on the manuals and Matt's videos, and could use some input on whatever else I'm missing.

Matt mentioned that on the MSB freight services, I should pretty much only run in PZB mode U. I also noticed in his video that he's going max 90 km/h (the usual limit for U is 105, or so I've read). If I understood correctly, this is because the brakes are set to the "goods" (= slower application) mode.

On the RSN, I see he mostly runs in mode M and up to the max speed of 125 km/h, as the mode dictates. (well, 120 mostly, but I guess that's to leave a little buffer) Any idea if this is because the RSN services are lighter, or maybe the DB 185.2 has better brakes? Would 143 or 182 also use PZB M on RSN?

For MSB, all the trains are sized to be well over the PZB-M limits, and are also set to "Goods Timing". The combination means that you are not only in PZB-U, but actually further limited to 90km/h, though the lower limit is not actually tested by the train, you will find it makes stopping more achievable.

There are some services that can be run by the 143 - if you run those services with a 182 or 185.2 then you can probably get away with running those in PZB-M if you want some variety and a faster run.

The Double header services you can probably get away with PZB-M too though technically they ought to be PZB-U.

I figured a good exercise/practical way to find out what PZB mode to run in game is ... find an active magnet, go over it with the max allowed speed, don't acknowledge => this triggers the emergency brakes, and now you just observe whether the train stops in time or not.

For example, when I did that on a yellow light in PZB M on MSB going 120 kph, the train rolled way past the red light. Clearly PZB M is a bad choice

Same test on RSN, going 120 kph, this time on a yellow speed limit sign, the train easily stopped 400-500 m before the actual speed limit.

I guess you could also just find a mile marker, put the brakes in emergency yourself, and observe where the train stops. Less than 1 km = good, more = not good (;

PS If anyone happens to know how they calculate this in real service, that would be some interesting piece of trivia. I started searching around and looks like it's not some rocket science, but not that trivial either, with a ton of factors like the weight of the train, the grades on the route, the kinds of cars and the specs of the brakes on these cars, etc. etc. Relatively simple math, just lots and lots of tables and know-how to go through?